Development of 94GHz microstrip line rectenna

In an RF energy wireless power transfer, it is a strong point to choose a millimeter-wave band. Because the system can be more compact-size caused by shorter wavelength. Then, it is possible to reduce a rectenna area if the rectified DC power is equivalent to a microwave rectenna. This is a great advantage for high power and light weight application like flying vehicles. In this study, a 94 GHz rectenna was developed and evaluated. Before integration, using finline, a rectifier and an antenna were evaluated separately. When load resistance is 125 $\Omega$ at the input power of 104 mW, rectifying efficiency was obtained by 46%. The gain of 16-element microstrip antenna (MSA) was 9.0 dBi. After integration, the rectifying efficiency of rectenna $(\eta_{rec})$ was 27.4% at the input power of 3S.0mW, and the rectenna conversion efficiency $(\eta_{con})$ was 2.75% at the receiving power of 37S mW. The measurement of the rectenna was performed under power condensed condition to increase the input power.